Kinases and phosphatases, such as glycogen synthase kinase (GSK-3β), calmodullin-dependent protein kinase II (CaMKII) and phosphoseryl/ phosphothreonyl protein phosphatase-2A (PP2A), are important enzymes involved in the regulation of hyperphosphorylation of tau protein in the development of AD (Gong et al., 1993, 1995; Pei et al., 1999; Vogelsberg-Ragaglia et al., 2001; Wang et al., 2005). Here, PTPA is linked to Alzheimer disease.